Cyclic Loading and Cyclic Stress

Synonyms

Definition

Cyclic loading is the application of repeated or fluctuating stresses, strains, or stress intensities to locations on structural components. The degradation that may occur at the location is referred to as fatigue degradation.

Scientific Fundamentals

Fatigue design of engineering components has been under intense study since the early days of its discovery in Europe in the early 1800s. After many years of study it became clear that a systems view of fatigue was needed to assure that all of the parameters involved in the fatigue process are considered adequately. Figure 1 shows the basic systems view proposed in 1971 (Hoeppner 1971). Only the initial parameters to be considered in a typical fatigue design are shown.

Cyclic Loading and Cyclic Stress, Fig. 1

A systems view of fatigue. Only initial parameters to be considered are shown (Hoeppner 1971)